Manufacture of filaments for electric lamps.



combining with t UNITED STATES PATENT. OFFICE.

EBANQOIS JEAN PLANCHQN, OF PARIS, FRANCE. I

MANUFACTURE OF FILAMENTS FOR ELECTRIC LAMPS.-

No Drawing.

Specification of Letters Patent. PatgntedAug, 23, 1910. Application filed July 5, 1907. Serial No. 382,326.

Lamps, of which the following is a 'specification.

At resent several processes are known where what are termed metallic filaments or incandescent electric lamps may be obtained, but the filaments so obtained do not give complete satisfaction, especially in view of the fact that they are frequently irregular in their dimensions or their re-.

sistance, so that before they can be used, it has been necessary to submit them to treatinents which are generally .complicated. Filaments which do not present these disadvantages may be, obtained by starting with chemical compounds which are perfectly homogeneous and capable of retaining this homogeneity throughout the entire duration of the successive operations to which they must' be subjected during their manufacture into filaments. J

Albuminoid and proteinaeeous substances, gelatin for exam le, have the property of he anhydrids and aci s of metals, such for example, as tungsten, mo-

lybdenum, uranium, titanium and tantalum, each of which pertains to the family of metals having a high melting point. In order to obtain these chemical combinations, the followin method, described generally, may'be emp oyed: An aqueous or alkaline uminoid material is mixed with a solution of an alkaline salt of the said'metals, then the whole is poured into a weak acid solution. A precipitate is so obtained which is washed'and is then ready to be formed into the filaments. As an example, twenty grams of albumen 4min alkaline solution may be mixed with one hundred grams of tungstic acid in the state of tungstate of sodium. This compound is then oured into one liter of a solution of chlor ydric acid (1/10 of acid). The precipitate obtained weighs '110 grams. and contains 80 per cent. of tungstic acid. Or, 18 grams of casein in alkaline solution and 72 grams of tungstic anhydrid (W0 in the state of tungstateof sodium may be ploured into one liter of a solution of chlor ydric JEAN PLA'N- acid (1/10 of acid) giving a precipitate weighing 90 grams and containing 80 per cent. of tungstic acid.

I have shown gelatin as an example of an albuminoid substance which may be combined with the metal, but it will be. understood that any equivalent albuminoid capable of producing the results herein described is to b'eincluded within the sec e. "of the claims.

I "also intend to include in the claims by the term acid of a metal of theclass described the anhydrids of such metals. v

This method is capable of very general application, and it may be used in the treatment of all albuminoid substances with the anh drids or acids of the following metals having a high .melting point: tungsten, molybdenum, uranium, titanium andtantalum, and it may also be used with the paraandmeta-tungstic, phospho-tungstic, phospho molybdic, silico tungstic and silicomolybdic acids.

In order to manufacture filaments or rods from the novel compounds just described, the procedure may be as follows One of these compiounds is taken and to it there is added a su cient quantity of water to form a more or less plastic mass which may then be, formed b any of the well known methods into the laments or articles of the desired dimensions and'shape. After the filaments have been thus formed and dried,-they are heated by any suitable means, and whlle air is excluded, to such a temperature that it becomes a conductor of electricity. The filament is then subjected to a final operation which consists in raising it progressively to a high temperature by means of an electric current in-a vessel in which a vacuum has previously been formed, or-which contains a gas which is inert or one at least which exerts no action upon the metal which enters into the initial composition.

One of the foregoin compounds may also be dissolved in an alkaline solution. This dissolved substance is given such a consistency that it is able to flow in. a continuous manner either under the influence of gravity or under the influence of an appropriate pressure, through an orifice of appropriate ment is 'then subjected to the same operations, as 'before.

I claiii jgas my invention 1. A'step in the process of manufacturing incandescent filaments from metals having a high fusing pointwhichconsists in forming a compoundof-an acid of such metal and an albuminoid substance, and treating the compound so formed with a weak acid solution.

2. The hereindescribed process of man u' facturing incandescent filaments from metals product to convert it into an electrical conuctor.

3. A ste in the rocess of manufacturing filaments or incan escent lamps from metals having a high fusing int, which consists in forming a compoun an albummoid substance and an alkaline salt of-suchmetal, andtreating the com-.

pound so formed with an acid to produce a precipitate which is a combinationof the albuminoid substance and the metal.

In testimon whereof I have hereunto set my hand in presence of two subscribing witnesses. I

FRANQOIS JEAN PLANOHON. Witnesses:

EMILE KLoTz, MAX DE RIRAUD.

from a solution of 

